With increasing development of science and technology, the performance of electronic devices is largely enhanced. Consequently, heat dissipating devices or heat dissipating systems become essential instruments for the electronic devices. During operation of an electronic device, a great amount of heat is generated by the electronic components of the electronic device. If the heat cannot be effectively dissipated away, the elevated operating temperature may result in damage, short circuit or deteriorated performance of the electronic device. For effectively removing the heat, it is important to install a high-performance heat dissipating device within or beside the electronic device to exhaust the heat to the surroundings. Moreover, the manufactures make efforts in increasing the efficiency of the heat dissipating device.
A fan is one of the most popular heat dissipating devices. As the performance of the electronic device is enhanced, it is important to increase the heat dissipating efficiency of the fan. For example, the increase of the channel within a frame of the fan can increase the amount of the produced airflow. However, in case that the channel is enlarged, the volume of the fan is also increased. Since the layout space of the electronic device is limited, it is difficult to install the large fan in the electronic device.
Moreover, the impeller of the conventional centrifugal fan is usually equipped with a single blade group. For increasing the amount of the produced airflow, it is necessary to increase the rotating speed. As the rotating speed is increased, the problem of generating noise becomes more serious. In accordance with another approach, the centrifugal fan is equipped with two impellers to increase the airflow amount. Each of the two impellers has a blade group, and the two blade groups of the two impellers are interlaced and assembled with each other. That is, the overall volume of the fan is also increased. Since the layout space of the electronic device is limited, it is difficult to install the large fan in the electronic device.
Therefore, there is a need of providing an impeller and a centrifugal fan with enhanced operating efficiency, reduced system impedance and reduced noise in order to overcome the drawbacks of the conventional technology.